Electric circuit interruption



June 25, 1940. Q A, KELLY ELECTRIC CIRCUIT INTERRUPTION Filed July 19, 1937 2 Sheets-Sheet l TU .PENE i June 25, 1940.

D. A. KELLY ELECTRIC CIRCUIT INTERRUPTION nl n,

/aQ/Wi Patented June 25, 1940 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to electric fences and contemplates an improvement in the mechanism for energizing the fence and particularly in one of the component parts thereof.

As clearly brought out in Reissue Patent No. 19,922, issued to Edwin J. Gengler April 7, 1936, electric fences are now intermittently energized, the actual fence wire being charged by an intermittently energized induction transformer. To this end, some type of timing device is employed in conjunction with a relay at which the energizing circuit is actually made and broken. The timing device periodically closes and opens a circuit, but its period of closure is too short to permit saturation or even near saturation of the transformer, if the transformer primary circuit were directly controlled by the timing device. Hence, the relay is provided. Its contacts remain closed for a longer period and thus compensate for the inherent lag of the transformer and permit the circuit for its primary to remain closed long enough to insure suiilcient saturation.

Heretofore, the contacts of the relay were closed by a cam construction or some similar device, but this arrangement proved unsatisfactory because of frequent failure and diilculty of adjustment.

With this objection in mind, the present invention has as one of its objects to provide an improved relay for the purpose set forth wherein the desired period of closure is obtained in an extremely simple and eflicient manner which allows ready adjustment of the duration of con-l tact closure.

Another object of this invention is to provide a readily removable relay unit so that in the event of failure or the necessity for any repair whatsoever on the relay unit, it may be bodily removed and replaced with a new unit.

Another object of this invention is to improve the construction of relays used for this purpose so as to facilitate the replacement and adjustment of its contacts.

More specifically it is an object of this invention to so utilize a spring blade in the mounting of the contacts that its inherent yieldability supplies the time interval during which the contacts are engaged.

Another object of this invention is to provide an improved manner of adjustably limiting the motion of the armature, so that its range of motion may be adjusted to suit different conditions.

With the above and other objects in view which will appear as the description proceeds,

this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described, and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete example'of the physical embodiment of the invention constructed in accordance with the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is an end view, with parts broken away and in section, of the relay used to open and close the transformer circuit;

Figure 2 is a front view of the complete energizing unit, illustrating the manner in which it is mounted within the enclosing cabinet and the ease with which the relay unit may be bodily removed;

Figure 3 is a diagrammatic view illustrating the circuit connections of the entire system;

Figure 4 is a front view of the relay unit with parts broken away and in section; and

Figure 5 is a horizontal sectional view through Figure 4 on the plane of the line 5-5.

Referring now particularly to the accompanying drawings in which like numerals indicate like parts, and particularly to Figure 3 thereof, the numeral 5 designates a battery or other source of electrical energy from which the entire mechanism is electrically charged. 'I'he battery 5 is connectible by a main switch B with one terminal of a timing device 1 through a conductor 8 and also through the same conductor with one side of the primary of a transformer I0.

'I'he timing device 'I may be of any suitable construction, and in the present instance consists of a weighted disc II mounted to rotate on fixed bearings and carrying a contact I2 which is normally held in engagement with an armature contact I3 by a torsion spring I4 acting on the rotary disc II and tending to hold the contacts I2 and I3 engaged.

The circuit from the battery continues through the disc II to the contacts I2 and I3 and then through an armature I5 to one side of a magnet coil I6 arranged to attract the armature upon energization thereof. Upon the energization of the magnet I6, the impulse imparted to the armature kicks the disc II in a direction to move its contact I2 out of engagement with the contact I3 thus breaking the energizing. circuit of the magnet I6. The torsion spring I4 then moves the disc II in a direction to engage the contacts and again energize the magnet. In this manner, the desired timing is derived.

The circuit traced so far through the timing device continues through conductor I1 to one side of a magnet coil I8 forming part of the relay unit, indicated generally by the numeral I9. From the other side of this magnet coil I3, the circuit is completed back to the battery 5 through a conductor 20.

The relay unit I3 is of novel construction as hereinafter to be described, and upon engagement of its contacts 2I andv 22, the circuit for energizing the transformer primary is completed through conductor 23 which leads from the trans-l former primary to the contact 2i, and through the closed contacts and the frame oi the relay which is connected through a conductor 24 and the conductor 20 to the other side of the battery 5. A condenser 25 is preferably connected across the primary of the transformer, as shown, and a balancing resistance 26 is interposed in the con ductor 23 to be connected in series with the transformer primary.

The secondary of the transfomer i3, preferably in two parts, has one end of each of its parts grounded as at 2l, and the other ends thereof selectively connectible through a switch 28 with the fence proper. As will be readily apparent, the intermittent energization of the transformer primary intermittently charges the fence connected with its secondary and through proper choice of the value of the resistor 23, a balancing eiect can be obtained to eliminate peak .io-ads and allow a smaller transformer to be used.

If desired, a signal 9 may be connected in series with the fence, as shown, to indicate the grounding of the fence.

'Ihe relay unit i3 consists of a substantially U-shaped frame 3B having the magnet coil mounted on its lower closed end. @ne arm of the U-shaped trame carries a support 3G from which an armature 32 is pivoted. A spring 3@ yieldingly holds the armature spaced from the pole piece 33 or the magnet.

The armature, as shown, comprises a substantially nat plate with its inner end arranged for pivotal support and its outer end reduced in width to project beyond the electromagnet i8 and also past the opposite end of the U-shaped frame. This end of the U-shaped frame has a bracket 35 iixed to its inner face but electrically insulated therefrom. The bracket 35 has the stationary contact 2I adjustably secured therein, as shown, and to facilitate adjustment of the contact 2I, the closed bottom of the frame has a hole 36 in line with the contact 2l to permit the insertion of a screw driver therethrough.

Projecting up from the top of this end of the U-shaped frame is another bracket 36 having an overhanging horizontal portion 31 in which an adjustable stop screw 38 is mounted to engage and limit upward travel of the armature.

By adjustment of the screw 38, the distance the armature moves from the pole piece of the magnet may be set so that when the battery strength drops below a predetermined minimum, the armature will not be actuated, thereby precluding an objectionably iight engagement of the contacts.

The movable contact 22 is xed to the outer free end of a spring blade 39 which overlies the top surface of the armature and is readily detachably secured thereto at its inner end by a screw Il threaded into the amature. The contact 22, as shown, projects through an opening in the armature.

Downward movement of the armature in response to energization of the electromagnet is limited by the engagement of its outer free end with a stop shoulder II forming part of the bracket 36'. This shoulder is so disposed-with respect to the top of the pole piece 33 that downward motion of the armature is arrested before it engages the pole piece to thereby prevent magnetic freezing, but prior to the engagement of the armature with the stop 4I, the movable contact 22 engages the stationary contact 2I so that the actual engagement of the contacts is under spring tension provided by the spring blade 38.

This manner of mounting the movable contact also provides the desired time interval for the closure of the contacts, as it maintains engage-'- ment of the contacts during the time required for the i'lnal closing motion of the armature and its equivalent initial motion in the opposite direction; and by adjusting the position of the stationary contact, this time interval may be either increased or decreased thus allowing the period of closure for the primary circuit to be so set as to secure the desired and most efficient degree of saturation for the transformer.

With reference to Figure 3, the operation of the device is as follows:

'Upon closure of the switch 6, a circuit is established from the battery through the contacts I2 and i 3, through the coil of the magnet I6 and then through the coil of the relay I8, back to the battery 5. Energization of the coil I8 attracts the armature of the relay and engages the contacts 2l and 22. Closure of the contacts 2| and 22, therefore, completes a circuit from the battery, through the conductors 2li-and 24, tothe frame of the relay, and through the contacts, back to the battery through the primary oi? the trans- :former i0.

Upon such energization of the transformer primary, an E. M. F. is impressed on the fence wire, the strength of which is determined by the position of the switch 28, which is selectively connectible to either of the sections of the secondary.

Energization of the relay coil IB is accompanied by energization of the magnet coil IB, whereupon the circuit to the relay coil I8 is broken by the impulse imparted to the armature i5 as it is attracted to its magnet to kick the disc II of the timing device in a direction to move its contact I2 out of engagement with the contact i3. The circuit to the primary of the transformer i0, however, is not immediately broken when the relay coil I8 is deenergized, inasmuch as the engagement of the contacts is maintained during the time required for the armature to move away from the pole piece in response to the spring 34 and into engagement with the contact carrier 39.

After the engagement of the armature with the contact ilnger 33, further motion of the armature lifts the contact 22 out of engagement with the contact 2I, such motion being arrested by the adjustable stop 38.

The fence wire is again energized upon engagement of the contacts I2 and I3 of the timing device in response to the torsion spring I 4 which re-engages the contacts 2| and 22 to complete the circuit for the primary of the transformen It is thus apparent that as long as the switch 3 remains closed, the fence wirewi1lperiodically receive` electrical impulses in response to the action of the timing device, and that the duration of `these impulses is dependent upon the length of time the contacts 2l and 22 remain in engagement.

The relay frame is mounted on a base of insulating material 45 to which the back 46 of a sheet metal housing is secured, the housing being completed by a removable cover 6l. The insulated base 45 has four prongs 48 Xed thereto and projecting rearwardly therefrom to engage in a suitable receptacle or socket. The prongs 48 have the four wire leads which come from the two sides of the magnet coil, from the frame of the magnet, and from the stationary contact connected thereto so that merely by the insertion of the prongs into the proper receptacles, the relay unit is electrically connected in the circuit. While a separate receptacle or socket may be employed to receive the prongs of the relay unit, the terminals 49 which the prongs engage in the present instance are shown as being secured to the back of a panel D mounted in an enclosing casing 5l in which the entire mechanism is housed.

The panel 50 is arranged within the body of the casing 5I spaced from its back wall and has the ti'ming device, the resistor 26 and the condensor 25 mounted in back of the panel. The signal light 9 is mounted in front of the panel as are the switches 6 and 28. The only other unit in front of the panel is the removable relay, as shown.

From the foregoing description taken in con nection with the accompanying drawings, it will be readily apparent to those skilled in the art, that this invention provides a substantial improvement in electric fences and particularly in the mechanism for electing intermittent energization thereof; and that it provides for readily adjusting the period of saturation for the energizing transformer so as to insure the greatest efficiency and eiectiveness for the fence.

What I claim as my invention is:

1. In combination: an induction transformer having a primary and a secondary; an energizing circuit for the primary; a relay to close said energizing circuit and having an electromagnet; another circuit for energizing the electromagnet of the relay; a timing device in said other circuit for momentarily closing the energizing circuit of the electromagnet with periodic regularity; and contacts engageable upon energization of the electromagnet of the relay to close the energizing circuit of the primary; one of said contacts being yieldable so that the period of engagement of said contacts may be longer than the time interval for which the electromagnet is energized to provide adequate time for saturation of the trans former.

2. In combination: an induction transformer having a primary and secondary; a circuit for energizing the primary; a relay having movable and stationary contacts adapted upon engagement to close the energizing circuit of the primary and having an electromagnet to elect engagement of its contacts; another circuit for energizing the electromagnet; a timing device in said other circuit to close the same momentarily with periodic regularity, and said relay including an armature movable upon energization of the electromagnet; a spring blade fastened to the armature and yieldingly mounting one of the contacts; and a stop to limit the contact closing motion of the armature, said stop being so located with respect to the other of said contacts as to function subsequently to initial engagement of the contacts so that the contacts are engaged for a time interval longer than that of the momentary energization of the electromagnet to insure suicient time for adequate saturation of the transformer. I

3. In a relay: an electromagnet having a pole piece; a movable armature biased away from said pole piece and adapted to be attracted to the pole piece upon energization of the electromagnet; a stationary contact; a movable contact; yieldable means for mounting the movable contact on the armature so that attraction of the armature toward the pole piece engages the movable contact with the stationary contact; stop means denning the extent of motion of the armature toward the pole piece, said stop means being positioned to prevent engagement of the armature with the pole piece upon energization of the electromagnet and so located with respect to the stationary contact as to act on the armature subsequently to the initial engagement of the contacts; means for adjusting the position of the stationary contact so that the time differential between initial contact engagement and the stopping of the armature motion may be regulated to provide adjustment for the duration of contact engagement; and an adjustable stop to limit the motion of the armature away from the pole piece in response to its biasing means at a point at which the armature lies beyond the pulling power of the electromagnet in the event of its energization by an inadequate E. M. F., but at a point where the armature is attracted by the electromagnet when sufficiently energized, thereby insuring firm engagement between the contacts.

DANIEL ALLCOTT KELLY. 

